TOP-STOP VERTICAL is a spray-applied, water-soluble surface retarder designed to slow the set of surface mortar in concrete to expose the aggregate. It temporarily halts the set of Portland cement at the surface while the concrete below the surface cures normally. TOP-STOP VERTICAL is economical and easy to use. The product is designed specifically for vertical surfaces. It will uniformly coat concrete forms, producing beautiful exposed aggregate concrete with consistent results. TOP-STOP VERTICAL is non-flammable and VOC-compliant.